1. Field of the Invention
The present invention relates to a thin film transistor substrate and a liquid crystal display that includes the thin film transistor substrate.
2. Description of the Related Art
In general, a liquid crystal display includes a display panel for displaying an image and a backlight unit for supplying light to the display panel. The display panel includes a thin film transistor substrate in which pixels are arranged in a matrix form, a color filter substrate overlapping the thin film transistor substrate, and a liquid crystal layer interposed between the thin film transistor substrate and the color filter substrate.
The thin film transistor substrate includes gate lines, data lines insulated from the gate lines and crossing the gate lines, and thin film transistors each being connected to a corresponding gate line of the gate lines and a corresponding data line of the data lines. Each pixel may receive a pixel voltage through a corresponding thin film transistor of the thin film transistors. An arrangement of liquid crystal molecules of the liquid crystal layer may be changed in accordance with the pixel voltage, and a transmittance of the light transmitted through the liquid crystal layer may change according to the arrangement of the liquid crystal molecules, thereby displaying a desired image.
Various inspections are required to detect defects when the display panel is manufactured. For example, the inspections may include an open/short test and a visual inspection.
The open/short test is applied to detect opens and shorts on the data lines formed on the thin film transistor substrate. For each data line of the data lines, the open/short test is performed by applying a test signal to one end of the data line and detecting the test signal from the other end of the data line. If a data line is open, the open data line is welded to a repair line. A data voltage (or data signal) is transmitted through the repair line to at least a portion of the open data line.
The visual inspection is performed by applying an inspection signal having a constant voltage level to the gate lines and the data lines, which are connected to the pixels of the thin film transistor substrate, and observing a resistance image (or resistance profile).